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Астронет: Астрономическая картинка дня Трубчатые облака над Небраской http://variable-stars.ru/db/msg/1880072/eng |
Credit & Copyright: Jorn Olsen Photography
Explanation:
When do cloud bottoms appear like bubbles?
Normally,
cloud bottoms are flat.
This is because moist warm air
that rises and cools will condense
into water droplets at a specific temperature,
which usually corresponds to a very specific height.
As water
droplets grow, an opaque cloud forms.
Under some conditions, however, cloud pockets can develop that contain large droplets
of water or ice that fall into clear air as they evaporate.
Such pockets may occur in
turbulent
air near a thunderstorm.
Resulting mammatus clouds can appear especially
dramatic if
sunlit from the side.
The
mammatus clouds
pictured here were photographed over
Hastings,
Nebraska
during 2004 June.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.